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Nishino, Shirley F., George C. Paoli i Jim C. Spain. "Aerobic Degradation of Dinitrotoluenes and Pathway for Bacterial Degradation of 2,6-Dinitrotoluene". Applied and Environmental Microbiology 66, nr 5 (1.05.2000): 2139–47. http://dx.doi.org/10.1128/aem.66.5.2139-2147.2000.
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ABSTRACT An oxidative pathway for the mineralization of 2,4-dinitrotoluene (2,4-DNT) by Burkholderia sp. strain DNT has been reported previously. We report here the isolation of additional strains with the ability to mineralize 2,4-DNT by the same pathway and the isolation and characterization of bacterial strains that mineralize 2,6-dinitrotoluene (2,6-DNT) by a different pathway.Burkholderia cepacia strain JS850 andHydrogenophaga palleronii strain JS863 grew on 2,6-DNT as the sole source of carbon and nitrogen. The initial steps in the pathway for degradation of 2,6-DNT were determined by simultaneous induction, enzyme assays, and identification of metabolites through mass spectroscopy and nuclear magnetic resonance. 2,6-DNT was converted to 3-methyl-4-nitrocatechol by a dioxygenation reaction accompanied by the release of nitrite. 3-Methyl-4-nitrocatechol was the substrate for extradiol ring cleavage yielding 2-hydroxy-5-nitro-6-oxohepta-2,4-dienoic acid, which was converted to 2-hydroxy-5-nitropenta-2,4-dienoic acid. 2,4-DNT-degrading strains also converted 2,6-DNT to 3-methyl-4-nitrocatechol but did not metabolize the 3-methyl-4-nitrocatechol. Although 2,6-DNT prevented the degradation of 2,4-DNT by 2,4-DNT-degrading strains, the effect was not the result of inhibition of 2,4-DNT dioxygenase by 2,6-DNT or of 4-methyl-5-nitrocatechol monooxygenase by 3-methyl-4-nitrocatechol.
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Cheng, Jiayang, Makram T. Suidan i Albert D. Venosa. "Kinetics of anaerobic cometabolism of 2,4-dinitrotoluene with ethanol as the primary substrate". Water Science and Technology 36, nr 6-7 (1.09.1997): 271–78. http://dx.doi.org/10.2166/wst.1997.0600.
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A kinetic model that describes the anaerobic cometabolism of 2,4-dinitrtoluene (DNT) with ethanol as the primary substrate has been developed based on experimental results. The kinetic parameters were estimated using the Levenberg-Marquardt algorithm. 2,4-DNT is anaerobically biotransformed to 2,4-diaminotoluene (DAT) via 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) by the bacteria whose growth is supported by utilizing ethanol. 2,4-DNT shows inhibition to its own biotransformation. It also exhibits a very strong competitive inhibition to further biotransformation of 4-A-2-NT and 2-A-4-NT. All the aromatics in the system, 2,4-DNT, 4-A-2-NT, 2-A-4-NT, and 2,4-DAT, inhibit the conversion of ethanol. Hydrogen produced from the acetogenesis of ethanol is utilized for the transformation of the nitroaromatics. The utilization of hydrogen and acetate by methanogenic bacteria is very strongly inhibited by the presence of the nitroaromatics. Acetate exhibits strong competitive inhibition to the biodegradation of propionate.
3
Huang, Zhong Hua, Xue Pu, Hui Zhang, Fang Yuan i Zheng Li Liu. "Biodegradation of 2, 4-Dinitrotoluene by Pseudomonas fluorescens sp. Isolated from a Nitrobenzene Contaminated Soil". Advanced Materials Research 610-613 (grudzień 2012): 1233–36. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.1233.
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A 2,4-Dinitrotoluene degrading bacterium was isolated from sludge contaminated by DNT and identified as a member of Pseudomonas fluorescens sp. based on 16S rDNA sequence. Under growth substrates limited conditions, the strain was enriched with 2,4-DNT as its sole source of carbon and energy in the groundwater environment. Results indicate the isolate grew optimally at 12(±4)°C and initial pH 7.5 in the mineral salts medium supplemented 2,4-DNT with 40mg/L, thus showing potential for the remediation of 2,4-DNT contaminated groundwater.
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Jiayang, Cheng, Makram T. Suidan i Albert D. Venosa. "Abiotic reduction of 2,4-dinitrotoluene in the presence of sulfide minerals under anoxic conditions". Water Science and Technology 34, nr 10 (1.11.1996): 25–33. http://dx.doi.org/10.2166/wst.1996.0235.
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Abiotic reduction of 2,4-dinitrotoluene (DNT) in the presence of sulfide minerals has been investigated under anoxic conditions at 35°C. 2,4-DNT was abiotically reduced to 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) in the presence of high concentration of sulfide (0.84 mM). No abiotic reduction of 2,4-DNT was observed in the presence of low sulfide concentration (0.42 mM). The rate and the extent of the abiotic reduction of 2,4-DNT were increased with an increase in sulfide concentration. Sulfide served as an electron donor for the reduction of 2,4-DNT. The 2-nitro group was preferentially reduced, making the 2-A-4-NT:4-A-2-NT ratio in the final products 2:1. The addition of iron, nickel, and cobalt minerals significantly enhanced the abiotic reduction. The FeS, NiS, and CoS solids formed in the serum bottles catalyzed the reduction of 2,4-DNT preferentially to 4-A-2-NT. MnS and CuS solids also catalyzed the reduction of 2,4-DNT to 4-A-2-NT, but did not change the overall reduction of 2,4-DNT. However, the presence of calcium, zinc, and magnesium minerals impeded 2,4-DNT reduction. The calcium, zinc, and magnesium ions have a high affinity to sulfide, inactivating sulfide as an electron donor for the chemical reduction of 2,4-DNT.
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Wang, Jing, Guang Fei Liu, Hong Lu, Ji Ti Zhou i Lihua Li. "Enhanced Biotransformation of Dinitrotoluene by Mediator-Functionalized Polypyrrole Composites". Advanced Materials Research 610-613 (grudzień 2012): 129–32. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.129.
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The continuous dosing and discharge of water soluble redox mediators such as biologically recalcitrant compounds will result in the secondary contamination. The immobilized redox mediator prepared by incorporation of anthraquinonedisulphon-ate (AQDS) during the electropolymerization of pyrrole monomer on active carbon felt (ACF), AQDS/PPy/ACF, was used for catalyzing bioreduction of 2,4-dinitrotoluene(2,4-DNT) in this study. The results showed that the morphology of the PPy films deposits on ACF are characterized by some globular structure; AQDS/PPy/ACF exhibited good catalytic activity and stability for 2,4-DNT, the enhanced reduction rates obtained in the incubations with AQDS/PPy/ACF was about 5 times that without AQDS/PPy/ACF, the corresponding first-order reduction rate constant k reached 0.045 h-1; 2,4-DNT was reduced to be 2,4-diaminotoluene via 2-amino-4-nitrotoluene and 4-amino-2-nitrotoluene in the system.
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Martin, J. L., S. D. Comfort, P. J. Shea, R. A. Drijber i T. A. Kokjohn. "Denitration of 2,4,6-trinitrotoluene byPseudomonas savastanoi". Canadian Journal of Microbiology 43, nr 5 (1.05.1997): 447–55. http://dx.doi.org/10.1139/m97-063.
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Past disposal of wastewaters containing 2,4,6-trinitrotoluene (TNT) at the former Nebraska Ordnance Plant has resulted in numerous acres of TNT-contaminated soil. Examining the microbial population of these soils revealed several TNT-tolerant Pseudomonas spp. We selected one species, P. savastanoi, to determine its ability to transform TNT. Pure culture experiments were performed in pseudomonas minimal medium containing 0.31 mM TNT (70 mg TNT∙L−1) under varied nutrient and cell density regimes. Experiments with TNT as a sole C or N source showed that P. savastanoi has the ability to denitrate TNT, as evidenced by production of 2,4-dinitrotoluene (2,4-DNT) and NO2−with time. TNT denitration and formation of 2,4-DNT were enhanced by removing NH4+and adding NO2−to the growth medium. In all experiments, 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) appeared as incidental reduction products. Glucose addition to the medium enhanced 2-ADNT and 4-ADNT production and decreased denitration of TNT. Mid-log phase cells rapidly transformed [ring-14C(U)]TNT but were unable to mineralize significant quantities of TNT, as evidenced by conversion of less than 1% of the label to14CO2. These results indicate that P. savastanoi is a TNT-tolerant pseudomonad that can promote TNT degradation through reductive denitration and nitro moiety reduction.Key words: TNT, biodegradation, transformation, reduction, nitrite.
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Mohammed, Mohammed S., Igor S. Kovalev, Natalya V. Slovesnova, Leila K. Sadieva, Vadim A. Platonov, Grigory A. Kim, Rammohan Aluru, Alexander S. Novikov, Olga S. Taniya i Valery N. Charushin. "(1-(4-(5-Phenyl-1,3,4-oxadiazol-2-yl)phenyl)-1H-1,2,3-triazol-4-yl)-methylenyls α,ω-Bisfunctionalized 3- and 4-PEG: Synthesis and Photophysical Studies". Molecules 28, nr 13 (6.07.2023): 5256. http://dx.doi.org/10.3390/molecules28135256.
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Two new azaheterocycle-based bolas, such as (1-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)-1H-1,2,3-triazol-4-yl)-methylenyls α,ω-bisfunctionalized PEGs, were prepared via Cu-catalyzed click reaction between 2-(4-azidophenyl)-5-(aryl)-oxadiazole-1,3,4 and terminal ethynyls derived from PEG-3 and PEG-4. Due to the presence of two heteroaromatic cores and a PEG linker, these bola molecules are considered as promising fluorescent chemosensors for electron-deficient species. As a result of a well-pronounced “turn-off” fluorescence response towards common nitro-explosive components, such as 2,4-dinitrotoluene (DNT) and 2,4,6-trinitrotoluene (TNT), hard-to-detect pentaerythritol tetranitrate (PETN), as well as Hg2+ cation was observed.
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Strehse, Jennifer Susanne, Tobias Hartwig Bünning, Jan Koschorreck, Anita Künitzer i Edmund Maser. "Long-Term Trends for Blue Mussels from the German Environmental Specimen Bank Show First Evidence of Munition Contaminants Uptake". Toxics 11, nr 4 (7.04.2023): 347. http://dx.doi.org/10.3390/toxics11040347.
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Submerged munitions are present in marine waters across the globe. They contain energetic compounds (ECs), such as TNT and metabolites thereof, which are considered carcinogenic, exhibit toxic effects in marine organisms, and may affect human health. The aim of this study was to investigate the occurrence of ECs and their trends in blue mussels from the annual collections of the German Environmental Specimen Bank sampled over the last 30 years at three different locations along the coastline of the Baltic and North Sea. Samples were analyzed by GC-MS/MS for 1,3-dinitrobenzene (1,3-DNB), 2,4-dinitrotoluene (2,4-DNT), 2,4,6-trinitrotoluene (TNT), 2-amino-4,6-dinitrotoluene (2-ADNT), and 4-amino-2,6-dinitrotoluene (4-ADNT). The first signals indicating trace levels of 1,3-DNB were observed in samples from 1999 and 2000. ECs were also found below the limit of detection (LoD) in subsequent years. From 2012 onwards, signals just above the LoD were detected. The highest signal intensities of 2-ADNT and 4-ADNT, just below the LoQ (0.14 ng/g d.w. and 0.17 ng/g d.w., respectively), were measured in 2019 and 2020. This study clearly shows that corroding submerged munitions are gradually releasing ECs into the waters that can be detected in randomly sampled blue mussels, even though the concentrations measured are still in the non-quantifiable trace range.
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Schick, Luca Aroha, Jennifer Susanne Strehse, Tobias Hartwig Bünning, Edmund Maser i Ursula Siebert. "Energetic Compounds in the Trophic Chain—A Pilot Study Examining the Exposure Risk of Common Eiders (Somateria mollissima) to TNT, Its Metabolites, and By-Products". Toxics 10, nr 11 (12.11.2022): 685. http://dx.doi.org/10.3390/toxics10110685.
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The Baltic and North Seas still contain large amounts of dumped munitions from both World Wars. The exposure of the munition shells to the seawater causes corrosion, which leads to the disintegration of shells and a leakage of energetic compounds, including the highly toxic 2,4,6-trinitrotoluene (TNT), and consequently threatening the marine environment. To evaluate the risk of accumulation of energetic compounds from conventional munitions in the marine food chain, we analyzed the presence of TNT and its metabolites 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) as well as their byproducts 1,3-dinitrobenzene (1,3-DNB) and 2,4-dinitrotoluene (2,4-DNT) in different tissues (including muscle, liver, kidney, brain, and bile) from 25 Common Eiders (Somateria mollissima) from the Danish Baltic Sea. Tissues were prepared according to approved protocols, followed by GC-MS/MS analysis. None of the aforementioned energetic compounds were detected in any of the samples. This pilot study is one of the first analyzing the presence of explosive chemicals in tissues from a free-ranging predatory species. This study highlights the need for continuous monitoring at different levels of the trophic chain to increase our knowledge on the distribution and possible accumulation of energetic compounds in the marine environment in order to provide reliable data for decision-making tools and risk assessments.
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Shukla, Nivedita, Vatsana Gupta, Ashok Singh Rawat, Vikas Kumar Gahlot, Sarita Shrivastava i Pramod Kumar Rai. "2, 4-Dinitrotoluene (DNT) and 2, 4, 6-Trinitrotoluene (TNT) removal kinetics and degradation mechanism using zero valent iron-silica nanocomposite". Journal of Environmental Chemical Engineering 6, nr 4 (sierpień 2018): 5196–203. http://dx.doi.org/10.1016/j.jece.2018.08.018.
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Moteleb, M. A., M. T. Suoidan, J. Kim, J. L. Davel i N. R. Adrian. "Anaerobic degradation of 2,4,6-trinitrotoluene in granular activated carbon fluidized bed and batch reactors". Water Science and Technology 43, nr 1 (1.01.2001): 67–75. http://dx.doi.org/10.2166/wst.2001.0016.
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In this study, an anaerobic fluidized bed reactor (AFBR) was used to treat a synthetically produced pink water waste stream containing trinitrotoluene (TNT). The synthesized waste consisted of 95 mg/l-TNT, the main contaminant in pink water, which was to be co-metabolized with 560-mg/l ethanol. Granular activated carbon was used as the attachment medium for biological growth. TNT was reduced to a variety of compounds, mainly 2,4,6-triaminotoluene (2,4,6-TAT), 2,4-diamino-6-nitrotoluene (2,4-DA-6-NT), 2,6-diamino-4-nitrotoluene (2,6-DA-4-NT), 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT), and 4-amino-2, 6-dinitrotoluene (4-A-2,6-DNT). These conversions resulted through the oxidation of ethanol to carbon dioxide under anoxic conditions, or reduction to methane under methanogenic conditions. The anaerobic reactor was charged with 1.0 kg of 16×20 U.S. Mesh Granular Activated Carbon (GAC) and was pre-loaded with 200g of TNT prior to the addition of the mixed seed culture. During the first three weeks of operation, ethanol was completely degraded and no methane was produced. Effluent inorganic carbon revealed stoichiometric conversion of the feed ethanol to dissolved inorganic carbon with accumulation of carbon dioxide in the headspace of the reactor. GAC extraction showed incremental reduction of the nitro groups to amino groups, with 2,4,6-TAT as the final product. After three weeks, the oxygen from the nitro groups was depleted and methane production commenced. The reproducibility of this phenomenon was confirmed by repeating the experiment in the same manner using an identical AFBR. Furthermore, serum bottle tests were conducted using TNT loading ratios of 0.2, 0.4, 0.8, 1.0 g-TNT/g-GAC as well as experiments in the absence of GAC. Similar behavior to that of the columns was observed, with degradation rates varying according to the particular condition. GAC greatly enhanced the degradation rates and the higher TNT loading resulted in slower degradation rates of ethanol.
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Hawari, Jalal, Annamaria Halasz, Sylvie Beaudet, Louise Paquet, Guy Ampleman i Sonia Thiboutot. "Biotransformation of 2,4,6-Trinitrotoluene withPhanerochaete chrysosporium in Agitated Cultures at pH 4.5". Applied and Environmental Microbiology 65, nr 7 (1.07.1999): 2977–86. http://dx.doi.org/10.1128/aem.65.7.2977-2986.1999.
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ABSTRACT The biotransformation of 2,4,6-trinitrotoluene (TNT) (175 μM) byPhanerochaete chrysosporium with molasses and citric acid at pH 4.5 was studied. In less than 2 weeks, TNT disappeared completely, but mineralization (liberated14CO2) did not exceed 1%. A time study revealed the presence of several intermediates, marked by the initial formation of two monohydroxylaminodinitrotoluenes (2- and 4-HADNT) followed by their successive transformation to several other products, including monoaminodinitrotoluenes (ADNT). A group of nine acylated intermediates were also detected. They included 2-N-acetylamido-4,6-dinitrotoluene and its pisomer, 2-formylamido-4,6-dinitrotoluene and its p isomer (as acylated ADNT), 4-N-acetylamino-2-amino-6-nitrotoluene and 4-N-formylamido-2-amino-6-nitrotoluene (as acetylated DANT), 4-N-acetylhydroxy-2,6-dinitrotoluene and 4-N-acetoxy-2,6-dinitrotoluene (as acetylated HADNT), and finally 4-N-acetylamido-2-hydroxylamino-6-nitrotoluene. Furthermore, a fraction of HADNTs were found to rearrange to their corresponding phenolamines (Bamberger rearrangement), while another group dimerized to azoxytoluenes which in turn transformed to azo compounds and eventually to the corresponding hydrazo derivatives. After 30 days, all of these metabolites, except traces of 4-ADNT and the hydrazo derivatives, disappeared, but mineralization did not exceed 10% even after the incubation period was increased to 120 days. The biotransformation of TNT was accompanied by the appearance of manganese peroxidase (MnP) and lignin-dependent peroxidase (LiP) activities. MnP activity was observed almost immediately after TNT disappearance, which was the period marked by the appearance of the initial metabolites (HADNT and ADNT), whereas the LiP activity was observed after 8 days of incubation, corresponding to the appearance of the acyl derivatives. Both MnP and LiP activities reached their maximum levels (100 and 10 U/liter, respectively) within 10 to 15 days after inoculation.
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Oda, Y., T. Shimada, M. Watanabe i T. Nohmi. "A Sensitive System (umu Test) for the Detection of Mutagenic Nitroarenes in Salmonella Typhimurium Strain Possessing Elevated Nitroreductase". Water Science and Technology 25, nr 11 (1.06.1992): 279–84. http://dx.doi.org/10.2166/wst.1992.0303.
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A sensitive test system for the detection of mutagenic nitroarenes in a new tester strain Salmonellatyphlmurium NM1011 with a high nitroreductase activity has been developed. The tester strain was constructed by subcloning the corresponding gene into pACYC184 plasmid, and introducingthe plasmid into TA1535 harboring a fusion gene umuc‘-'lacZ (pSK1002). The strain enablesus to monitor expression of the SOS function umuC, by measuring the β-galactosidase activity in the cells. The sensitivity of the NM1011 was compared with that of parent tester strain (TA1535/pSK1002), or a nitroreductase deficient strain in seventeen mutagenic/carcinogenic nitroarenes. The newly developed strains with a high nitroreductase activity had about 4 times higher nitrofurazone-reductase activity than the parent strain, and was found to be highly sensitive to the compounds such as 2-nitrofluorene (2-NF), 1-nitronaphthalene (1-NN), 2-nitronaphthalene (2-NN), 1-nitropyrene (1-NP), m-dinitrobenzene (m-DNB), 4,4’-dinitrobiphenyl (4,4’-DNB), 3-nitrofluoranthene, 3,7- and 3,9-dinitrofluoranthene, 5-nitroacenaphthene (5-NA), 1,6-dinitropyrene, and 2,4-dinitrotoluene (2,4-DNT). On the contrary, the enzyme-deficient strain did not show considerable responses to 2-NF, m-DNB, 1-NN, 2-NN, 1-NP, 4,4’-DNB, 2,4-DNT, and 5-NA. These results suggest that a newly developed tester strain that has high nitroreductase activity is very useful for the detection of mutagenic nitroarenes contaminating the water and urban atmosphere.
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Keenan, Brendan G., Thammajun Leungsakul, Barth F. Smets, Masa-aki Mori, David E. Henderson i Thomas K. Wood. "Protein Engineering of the Archetypal Nitroarene Dioxygenase of Ralstonia sp. Strain U2 for Activity on Aminonitrotoluenes and Dinitrotoluenes through Alpha-Subunit Residues Leucine 225, Phenylalanine 350, and Glycine 407". Journal of Bacteriology 187, nr 10 (15.05.2005): 3302–10. http://dx.doi.org/10.1128/jb.187.10.3302-3310.2005.
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ABSTRACT Naphthalene dioxygenase (NDO) from Ralstonia sp. strain U2 has not been reported to oxidize nitroaromatic compounds. Here, saturation mutagenesis of NDO at position F350 of the α-subunit (NagAc) created variant F350T that produced 3-methyl-4-nitrocatechol from 2,6-dinitrotoluene (26DNT), that released nitrite from 23DNT sixfold faster than wild-type NDO, and that produced 3-amino-4-methyl-5-nitrocatechol and 2-amino-4,6-dinitrobenzyl alcohol from 2-amino-4,6-dinitrotoluene (2A46DNT) (wild-type NDO has no detectable activity on 26DNT and 2A46DNT). DNA shuffling identified the beneficial NagAc mutation G407S, which when combined with the F350T substitution, increased the rate of NDO oxidation of 26DNT, 23DNT, and 2A46DNT threefold relative to variant F350T. DNA shuffling of NDO nagAcAd also generated the NagAc variant G50S/L225R/A269T with an increased rate of 4-amino-2-nitrotoluene (4A2NT; reduction product of 2,4-dinitrotoluene) oxidation; from 4A2NT, this variant produced both the previously uncharacterized oxidation product 4-amino-2-nitrocresol (enhanced 11-fold relative to wild-type NDO) as well as 4-amino-2-nitrobenzyl alcohol (4A2NBA; wild-type NDO does not generate this product). G50S/L225R/A269T also had increased nitrite release from 23DNT (14-fold relative to wild-type NDO) and generated 2,3-dinitrobenzyl alcohol (23DNBA) fourfold relative to wild-type NDO. The importance of position L225 for catalysis was confirmed through saturation mutagenesis; relative to wild-type NDO, NDO variant L225R had 12-fold faster generation of 4-amino-2-nitrocresol and production of 4A2NBA from 4A2NT as well as 24-fold faster generation of nitrite and 15-fold faster generation of 23DNBA from 23DNT. Hence, random mutagenesis discovered two new residues, G407 and L225, that influence the regiospecificity of Rieske non-heme-iron dioxygenases.
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Leungsakul, Thammajun, Glenn R. Johnson i Thomas K. Wood. "Protein Engineering of the 4-Methyl-5-Nitrocatechol Monooxygenase from Burkholderia sp. Strain DNT for Enhanced Degradation of Nitroaromatics". Applied and Environmental Microbiology 72, nr 6 (czerwiec 2006): 3933–39. http://dx.doi.org/10.1128/aem.02966-05.
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ABSTRACT 4-Methyl-5-nitrocatechol (4M5NC) monooxygenase (DntB) from Burkholderia sp. strain DNT catalyzes the second step of 2,4-dinitrotoluene degradation by converting 4M5NC to 2-hydroxy-5-methylquinone with the concomitant removal of the nitro group. DntB is a flavoprotein that has a very narrow substrate range. Here, error-prone PCR was used to create variant DntB M22L/L380I, which accepts the two new substrates 4-nitrophenol (4NP) and 3-methyl-4-nitrophenol (3M4NP). At 300 μM of 4NP, the initial rate of the variant expressing M22L/L380I enzyme (39 � 6 nmol/min/mg protein) was 10-fold higher than that of the wild-type enzyme (4 � 2 nmol/min/mg protein). The values of k cat/Km of the purified wild-type DntB enzyme and purified variant M22L/L380I were 40 and 450 (s−1 M−1), respectively, which corroborates that the variant M22L/L380I enzyme has 11-fold-higher efficiency than the wild-type enzyme for 4NP degradation. In addition, the variant M22L/L380I enzyme has fourfold-higher activity toward 3M4NP; at 300 μM, the initial nitrite release rate of M22L/L380I enzyme was 17 � 4 nmol/min/mg protein, while that of the wild-type enzyme was 4.4 � 0.7 nmol/min/mg protein. Saturation mutagenesis was also used to further investigate the role of the individual amino acid residues at positions M22, L380, and M22/L380 simultaneously. Mutagenesis at the individual positions M22L and L380I did not show appreciable enhancement in 4NP activity, which suggested that these two sites should be mutated together; simultaneous saturation mutagenesis led to the identification of the variant M22S/L380V, with 20% enhanced degradation of 4NP compared to the variant M22L/L380I. This is the first report of protein engineering for nitrite removal by a flavoprotein.
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Turner, Nicholas W., Clovia I. Holdsworth, Adam McCluskey i Michael C. Bowyer. "N-2-Propenyl-(5-dimethylamino)-1-naphthalene Sulfonamide, a Novel Fluorescent Monomer for the Molecularly Imprinted Polymer-Based Detection of 2,4-Dinitrotoluene in the Gas Phase". Australian Journal of Chemistry 65, nr 10 (2012): 1405. http://dx.doi.org/10.1071/ch12155.
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Fluorescent molecularly imprinted polymers (MIP) specific for 2,4-dinitrotoluene (DNT) have been synthesised using a novel monomer N-2-propenyl-(5-dimethylamino)-1-naphthalene sulfonamide. Three formats of the polymer were produced: a traditional bulk monolith ground into particles, a flexible, but highly cross-linked plasticiser-modified free standing membrane, and a hybrid material consisting of particles embedded in a poly(acrylonitrile) phase inversed film. Within all materials, a clearly defined imprinting effect was observed upon exposure to DNT vapour at room temperature. In all cases, preferential rebinding of DNT to the molecularly imprinted materials (3–5 times) over their non-imprinted (NIP) equivalents was evident within <10 min of contact with the DNT vapour stream. Fluorographic images of the fluorescent polymers showed the DNT binding-induced quenching to be significantly higher in the MIP material than in the non-imprinted control polymer.
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Rani, Sushma, Bharti Sharma, Shivani Kapoor, Rajesh Malhotra, Rajender S. Varma i Neeraj Dilbaghi. "Construction of Silver Quantum Dot Immobilized Zn-MOF-8 Composite for Electrochemical Sensing of 2,4-Dinitrotoluene". Applied Sciences 9, nr 22 (18.11.2019): 4952. http://dx.doi.org/10.3390/app9224952.
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In the present study, we report a highly effective electrochemical sensor for detecting 2,4-dinitrotoluene (2,4-DNT). The amperometric determination of 2,4-DNT was carried out using a gold electrode modified with zinc–metal organic framework-8 and silver quantum dot (Zn-MOF-8@AgQDs) composite. The synthesized nanomaterials were characterized by using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The synthesized nanocomposite proved to be efficient in electro-catalysis thereby reducing the 2,4-DNT. The unique combination present in Zn-MOF-8@AgQDs composite offered an excellent conductivity and large surface area enabling the fabrication of a highly sensitive (−0.238 µA µM−1 cm−2), selective, rapid and stable 2,4-DNT sensor. The dynamic linear range and limit of detection (LOD) was about 0.0002 µM to 0.9 µM and 0.041 µM, respectively. A 2,4-DNT reduction was also observed during the linear sweep voltammetry (LSV) experiments with reduction peaks at −0.49 V and −0.68 V. This is an unprecedented report with metal organic framework (MOF) composite for sensing 2,4-DNT. In addition, the presence of other species such as thiourea, urea, ammonia, glucose, and ascorbic acid displayed no interference in the modified electrode suggesting its practicability in various environmental applications.
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Ellis, H. V., C. B. Hong, C. C. Lee, J. C. Dacre i J. P. Glennon. "Subchronic and Chronic Toxicity Studies of 2,4-Dinitrotoluene. Part I. Beagle Dogs". Journal of the American College of Toxicology 4, nr 4 (lipiec 1985): 233–42. http://dx.doi.org/10.3109/10915818509078676.
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Subchronic and chronic toxicities of 2,4-dinitrotoluene (2,4-DNT) were studied in beagle dogs. The major adverse effect of 2,4-DNT in dogs was a neuropathy, characterized by incoordination and paralysis. There were vacuolation, endothelial proliferation, and gliosis of the cerebellums of some affected dogs. These effects were seen in 1 dog given 1.5 mg/kg per day for 2 years, in all dogs given 10 mg/kg per day within 6 months, and in all dogs given 25 mg/kg per day within 2 months. There was great variation between individuals in onset and severity of adverse effects. Some dogs progressed to a complete paralysis, leading to death. Methemoglobin and its sequelae were common, but not life threatening. Heinz bodies were a useful indicator of this effect. Less important adverse effects seen included testicular degeneration and biliary tract hyperplasia. No changes were found in tumor incidence, immunoglobin E and cytogenetic assays, and other routine hematologic and clinical laboratory tests.
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Modi, Krunal, Urvi Panchal, Chirag Patel, Keyur Bhatt, Shuvankar Dey, Divya Mishra i V. K. Jain. "Dual in vitro and in silico analysis of thiacalix[4]arene dinaphthalene sulfonate for the sensing of 4-nitrotoluene and 2,3-dinitrotoluene". New Journal of Chemistry 42, nr 4 (2018): 2682–91. http://dx.doi.org/10.1039/c7nj03820h.
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A newly synthesized thiacalix[4]arene dinaphthalene sulfonate, i.e., TCDNS, has been used as a fluorescence quencher for 2,3-DNT as well as 4-NT. The complex was analyzed by ESI-MS and 1H-NMR titration, which has been further confirmed by the in silico study.
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Smets, Barth F., R. Guy Riefler, Urs Lendenmann i Jim C. Spain. "Kinetic analysis of simultaneous 2,4-dinitrotoluene (DNT) and 2,6-DNT biodegradation in an aerobic fluidized-bed biofilm reactor". Biotechnology and Bioengineering 63, nr 6 (20.06.1999): 642–53. http://dx.doi.org/10.1002/(sici)1097-0290(19990620)63:6<642::aid-bit2>3.0.co;2-b.
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Parales, Juanito V., Rebecca E. Parales, Sol M. Resnick i David T. Gibson. "Enzyme Specificity of 2-Nitrotoluene 2,3-Dioxygenase from Pseudomonas sp. Strain JS42 Is Determined by the C-Terminal Region of the α Subunit of the Oxygenase Component". Journal of Bacteriology 180, nr 5 (1.03.1998): 1194–99. http://dx.doi.org/10.1128/jb.180.5.1194-1199.1998.
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ABSTRACT Biotransformations with recombinant Escherichia coliexpressing the genes encoding 2-nitrotoluene 2,3-dioxygenase (2NTDO) from Pseudomonas sp. strain JS42 demonstrated that 2NTDO catalyzes the dihydroxylation and/or monohydroxylation of a wide range of aromatic compounds. Extremely high nucleotide and deduced amino acid sequence identity exists between the components from 2NTDO and the corresponding components from 2,4-dinitrotoluene dioxygenase (2,4-DNTDO) from Burkholderia sp. strain DNT (formerlyPseudomonas sp. strain DNT). However, comparisons of the substrates oxidized by these dioxygenases show that they differ in substrate specificity, regiospecificity, and the enantiomeric composition of their oxidation products. Hybrid dioxygenases were constructed with the genes encoding 2NTDO and 2,4-DNTDO. Biotransformation experiments with these hybrid dioxygenases showed that the C-terminal region of the large subunit of the oxygenase component (ISPα) was responsible for the enzyme specificity differences observed between 2NTDO and 2,4-DNTDO. The small subunit of the terminal oxygenase component (ISPβ) was shown to play no role in determining the specificities of these dioxygenases.
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Barata, Patrícia D., i José V. Prata. "Fluorescent Calix[4]arene-Carbazole-Containing Polymers as Sensors for Nitroaromatic Explosives". Chemosensors 8, nr 4 (10.12.2020): 128. http://dx.doi.org/10.3390/chemosensors8040128.
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Two highly fluorescent calix[4]arene-containing phenylene-alt-ethynylene-carbazolylene polymers (Calix-PPE-CBZs) were used in the detection of explosives from the nitroaromatic compounds (NACs) family, in solution and in vapour phases. Both fluorophores exhibit high sensitivity and selectivity towards NACs detection. The quenching efficiencies in solution, assessed through static Stern-Volmer constants (KSV), follow the order picric acid (PA) >> 2,4,6-trinitrotoluene (TNT) > 2,4-dinitrotoluene > (2,4-DNT) > nitrobenzene (NB). These correlate very well with the NACs electron affinities, as evaluated from their lowest unoccupied molecular orbitals (LUMOs) energies, indicating a photo-induced electron transfer as the dominant mechanism in fluorescence quenching. Moreover, and most interesting, detection of TNT, 2,4-DNT and NB vapours via thin-films of Calix-PPE-CBZs revealed a remarkably sensitive response to these analytes, comparable to state-of-the-art chemosensors. The study also analyses and compares the current results to previous disclosed data on the detection of NACs by several calix[4]arene-based conjugated polymers and non-polymeric calix[4]arenes-carbazole conjugates, overall highlighting the superior role of calixarene and carbazole structural motifs in NACs’ detection performance. Density functional theory (DFT) calculations performed on polymer models were used to support some of the experimental findings.
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Aguado, Roberto, A. Rita M. G. Santos, Saúl Vallejos i Artur J. M. Valente. "Paper-Based Probes with Visual Response to Vapors from Nitroaromatic Explosives: Polyfluorenes and Tertiary Amines". Molecules 27, nr 9 (2.05.2022): 2900. http://dx.doi.org/10.3390/molecules27092900.
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Although it is well-known that nitroaromatic compounds quench the fluorescence of different conjugated polymers and form colored Meisenheimer complexes with proper nucleophiles, the potential of paper as a substrate for those macromolecules can be further developed. This work undertakes this task, impregnating paper strips with a fluorene-phenylene copolymer with quaternary ammonium groups, a bisfluorene-based cationic polyelectrolyte, and poly(2-(dimethylamino)ethyl methacrylate) (polyDMAEMA). Cationic groups make the aforementioned polyfluorenes attachable to paper, whose surface possesses a slightly negative charge and avoid interference from cationic quenchers. While conjugated polymers had their fluorescence quenched with nitroaromatic vapors in a non-selective way, polyDMAEMA-coated papers had a visual response that was selective to 2,4,6-trinitrotoluene (TNT), and that could be easily identified, and even quantified, under natural light. Far from implying that polyfluorenes should be ruled out, it must be taken into account that TNT-filled mines emit vapors from 2,4-dinitrotoluene (DNT) and dinitrobenzene isomers, which are more volatile than TNT itself. Atmospheres with only 790 ppbv TNT or 277 ppbv DNT were enough to trigger a distinguishable response, although the requirement for certain exposure times is an important limitation.
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Keenan, Brendan G., i Thomas K. Wood. "Orthric Rieske dioxygenases for degrading mixtures of 2,4-dinitrotoluene/naphthalene and 2-amino-4,6-dinitrotoluene/4-amino-2,6-dinitrotoluene". Applied Microbiology and Biotechnology 73, nr 4 (grudzień 2006): 827–38. http://dx.doi.org/10.1007/s00253-006-0538-8.
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Quinn, Michael J., Craig A. McFarland, Emily M. LaFiandra, Matthew A. Bazar i Mark S. Johnson. "Acute, subacute, and subchronic exposure to 2A-DNT (2-amino-4,6-dinitrotoluene) in the northern bobwhite (Colinus virginianus)". Ecotoxicology 19, nr 5 (9.03.2010): 945–52. http://dx.doi.org/10.1007/s10646-010-0476-1.
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López-Ruiz, Nuria, Miguel M. Erenas, Ignacio de Orbe-Payá, Luis F. Capitán-Vallvey, Alberto J. Palma i Antonio Martínez-Olmos. "Computer Vision-Based Portable System for Nitroaromatics Discrimination". Journal of Sensors 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/7087013.
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A computer vision-based portable measurement system is presented in this report. The system is based on a compact reader unit composed of a microcamera and a Raspberry Pi board as control unit. This reader can acquire and process images of a sensor array formed by four nonselective sensing chemistries. Processing these array images it is possible to identify and quantify eight different nitroaromatic compounds (both explosives and related compounds) by using chromatic coordinates of a color space. The system is also capable of sending the obtained information after the processing by a WiFi link to a smartphone in order to present the analysis result to the final user. The identification and quantification algorithm programmed in the Raspberry board is easy and quick enough to allow real time analysis. Nitroaromatic compounds analyzed in the range of mg/L were picric acid, 2,4-dinitrotoluene (2,4-DNT), 1,3-dinitrobenzene (1,3-DNB), 3,5-dinitrobenzonitrile (3,5-DNBN), 2-chloro-3,5-dinitrobenzotrifluoride (2-C-3,5-DNBF), 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), and tetryl (TT).
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Wang, Wen, Guowei Deng, Zhanwei Hu, Kaixin Chen i Jieyun Wu. "Sensitive Evanescence-Field Waveguide Interferometer for Aqueous Nitro-Explosive Sensing". Chemosensors 11, nr 4 (15.04.2023): 246. http://dx.doi.org/10.3390/chemosensors11040246.
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The development of novel chemical nitro-explosive sensors with high sensitivity, low cost and a compact size is essential for homeland security, environmental protection and addressing military challenges. Polymeric optical waveguides based on refractive index sensing are widely used in biochemical detection due to their advantages of large-scale integration, low cost, high sensitivity and anti-electromagnetic interference. In this study, we designed and fabricated a polymer waveguide Mach–Zehnder interferometer (MZI) sensor to detect 2,4-dinitrotoluene (DNT) in water. One phase shifter of the MZI waveguide was functionalized by coating a thin cladding layer of polycarbonate with dipolar chromophores and used as the sensing arm; the other arm was coated with passive epoxy resin cladding and used as the reference arm. The phase difference between the two arms of the MZI was modulated using the refractive index (RI) change in the polycarbonate cladding when dipolar chromophores interacted with electro-deficient DNT. The theoretical sensitivity of the designed MZI can reach up to 24,696 nm/RIU. When used for explosive detection, our fabricated sensor had a maximum wavelength shift of 4.465 nm and good linear relation, with an R2 of 0.96 between the wavelength shift and a concentration ranging from 3.5 × 10−5 to 6.3 × 10−4 mol/L. The sensitivity of our device was 6821.6 nm/(mol/L). The design of an unbalanced MZI sensor, together with the sensing material, provides a new approach to using low-cost, compact and highly sensitive devices for in-field explosive detection.
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Riefler, R. Guy, i Barth F. Smets. "NAD(P)H:Flavin Mononucleotide Oxidoreductase Inactivation during 2,4,6-Trinitrotoluene Reduction". Applied and Environmental Microbiology 68, nr 4 (kwiecień 2002): 1690–96. http://dx.doi.org/10.1128/aem.68.4.1690-1696.2002.
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ABSTRACT Bacteria readily transform 2,4,6-trinitrotoluene (TNT), a contaminant frequently found at military bases and munitions production facilities, by reduction of the nitro group substituents. In this work, the kinetics of nitroreduction were investigated by using a model nitroreductase, NAD(P)H:flavin mononucleotide (FMN) oxidoreductase. Under mediation by NAD(P)H:FMN oxidoreductase, TNT rapidly reacted with NADH to form 2-hydroxylamino-4,6-dinitrotoluene and 4-hydroxylamino-2,6-dinitrotoluene, whereas 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene were not produced. Progressive loss of activity was observed during TNT reduction, indicating inactivation of the enzyme during transformation. It is likely that a nitrosodinitrotoluene intermediate reacted with the NAD(P)H:FMN oxidoreductase, leading to enzyme inactivation. A half-maximum constant with respect to NADH, KN , of 394 μM was measured, indicating possible NADH limitation under typical cellular conditions. A mathematical model that describes the inactivation process and NADH limitation provided a good fit to TNT reduction profiles. This work represents the first step in developing a comprehensive enzyme level understanding of nitroarene biotransformation.
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Slížová, Dáša, Petr Šíma, Josef Richter, Otakar Krs i Jana Zavadilová. "Stimulation of Ileal Epithelium Growth and Regeneration by Dietary Nucleotide Extracts". Acta Medica (Hradec Kralove, Czech Republic) 47, nr 3 (2004): 163–66. http://dx.doi.org/10.14712/18059694.2018.84.
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The gastrointestinal tract epithelium plays an important role not only in digestion and absorption of nutrients, but also in antigen and pathogen signal translocation toward the gut associated lymphoid tissue. Malnutrition in various degrees is recognized as the most common cause of the immune system dysfunction. Research done in the past several years has revealed that dietary nucleotides (dNT) represent an essential compound of nutrition because of their importance in metabolic pathways, energetic processes and nucleic acid synthesis during tissue renewal. Much evidence accumulated suggests that dNT are essential for the growth and maturation of the gut epithelia. In previous experiments we have documented immunoregulative properties of dNT- containing extracts. In this study Balb/c female mice were fed (1) standard diet, (2) dNT-supplemented diet, and (3) dNT-supplemented water for 4 weeks. The supplement in dose of 100 mg/kg/l comprised original extract (Imuregen, Uniregen Ltd., Náchod, Czech Republic). Samples of terminal ileum in each dietary group were removed for histological examination. The length of villi was evaluated by computer morphometry. The highest growth of intestinal villi was observed in group administered dNT-supplemented water. We have found no pathological changes of intestinal epithelium in any experimental group.
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Quinn, Michael J., Terry L. Hanna, Alicia A. Shiflett, Craig A. McFarland, Michelle E. Cook, Mark S. Johnson, Kurt A. Gust i Edward J. Perkins. "Interspecific effects of 4A-DNT (4-amino-2,6-dinitrotoluene) and RDX (1,3,5-trinitro-1,3,5-triazine) in Japanese quail, Northern bobwhite, and Zebra finch". Ecotoxicology 22, nr 2 (17.11.2012): 231–39. http://dx.doi.org/10.1007/s10646-012-1019-8.
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ROSEMBERG, SÉRGIO, i GLACY S. VIEIRA. "Tumor neuroepitelial disembrioplástico: estudo epidemiológico de uma única instituição". Arquivos de Neuro-Psiquiatria 56, nr 2 (czerwiec 1998): 232–36. http://dx.doi.org/10.1590/s0004-282x1998000200011.
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A real incidência do tumor neuroepitelial disembrioplástico (DNT) é desconhecida. Diferentes estimações foram feitas, de acordo com o tipo de recrutamento dos pacientes. Nas séries provenientes de pacientes operados por epilepsia fármaco-resistente, as taxas variam amplamente, de 5% a 87%. Em uma série de 600 tumores pediátricos do sistema nervoso central, 9 DNT foram encontrados (1,5%). Como o DNT foi identificado apenas em 1988, revimos nossos casos (1975-1991) de gangliogliomas (n=25), oligoastrocitomas (n=9), oligodendrogliomas do lobo temporal (n=11), astrocitomas grau II (OMS 1993) (n=44), independentemente da idade dos pacientes, bem como todos os astrocitomas grau II (n=61) e oligodendrogliomas (n=10) em pacientes até a idade de 20 anos. Sete DNT foram encontrados. Quatro haviam sido previamente diagnosticados como gangliogliomas e 3, como astrocitomas grau II. A partir de 1992, 4 outros DNT foram diagnosticados, perfazendo um total de 11 casos. Oito pacientes tinham menos de 17 anos (6 a 17, média 10,3 anos) e três tinham 27, 42 e 51 anos. Oito tumores eram temporais, 1 frontal e 2 occipitais. Todos os pacientes apresentavam epilepsia fármaco-resistente. Dentre todos os tumores neuroepiteliais diagnosticados em nosso Serviço nos últimos 22 anos, DNT compreedem 1,2% em pacientes até 20 anos (n=660), 0,24% em pacientes acima de 20 anos (n=1254), e 0,63% na totalidade dos pacientes (n=1914).
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Yang, Liming, Dan Wang, Shangzhi Xu, Liuyang Wang, Jianjun Tong, Honglin Zhu, Man Xu i in. "Abstract 5510: Preclinical study of allogeneic CD19-CAR-DNT cells as an off-the-shelf immunotherapy drug for NHL". Cancer Research 82, nr 12_Supplement (15.06.2022): 5510. http://dx.doi.org/10.1158/1538-7445.am2022-5510.
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Abstract Introduction Allogeneic Double Negative T (DNT, CD3+CD4-CD8-) cells have shown great potential as a novel off-the-shelf immunotherapy drug candidate in clinic trials for r/r/AML patients. This is our first report to demonstrate that CD19-CAR-DNT cells with high percentage of Tscm+Tcm phenotypes have been successfully developed with strong immunotherapeutic effects on Raji-luciferase tumor cells from non-Hodgkin’s lymphoma both in vitro and in vivo. Methods DNT cells were expanded ex vivo from healthy donors and then were transduced with CD19-CAR lentivirus in the presence of IL-2. The CD19-CAR-DNT cell expansions were performed under GMP condition and then harvested and cryo-preserved by CryStor®CS5 in liquid nitrogen for future use. Summary The ex vivo expanded CD19-CAR-DNT cells has more than 50% of Tscm and Tcm phenotypes. The viability and CAR+ percentage of CD19-CAR-DNT cells were 84.40% and 34.98% respectively. The killing of CD19-CAR-DNT cells on Raji-luciferase cells was 77.92% (n=6) at the effector to target ratio of 4:1. Elevated IFN-γ release from CD19-CAR-DNT cells after overnight co-culture with Raji cells was observed. The antitumor efficacy was evaluated in the xenografted NHL mice model. After the first infusion of the cells, the tumor growth inhibitory rates (TGI %) of CD19-CAR-DNT cells at 1×106, 5×106 and 1×107 per mouse on day14 were 80.54%, 98.31% and 99.05% respectively, the killing effects were in a dose-dependent manner. After the second infusion of the CD19-CAR-DNT cells at day 14, median survival times (MST) of the treated three groups mice were elongated till Day60, that is twice longer than that of the xenografted vehicle group. In the subsequent PKPD study, infusion CD19-CAR-DNT cells into Raji-luciferase cell xenografted mice were primarily distributed in lungs, peripheral blood, spleen, and bone marrow within 72h, homing back to liver and spleen on Day36. All animal body weights in both fresh and frozen reconstituted CD19-CAR-DNT cells treated mice were increased with no observed toxicities. Conclusions ex vivo expansion of CD19-CAR-DNT cells were successfully developed to explore its potential as a novel off-the-shelf universal CART drug for malignant B cells leukemia. The cell subsets consist of more than 50% of Tscm and Tcm cells whereas most immunological check point inhibitors were not elevated after priming by target tumor cells except a slight increase of PD-1 molecule. Fresh or frozen CD19-CAR-DNT cells can kill Raji cells in vitro and in vivo studies in a dose-dependent manner although the frozen one showed a delayed killing in vivo. The tumor cells were almost depleted and the MST was significantly increased with NOAEL at 1x107 cells/mouse. The amounts of CD19-CAR-DNT cells are re-distributed from early lungs, peripheral blood to live, spleen later. Citation Format: Liming Yang, Dan Wang, Shangzhi Xu, Liuyang Wang, Jianjun Tong, Honglin Zhu, Man Xu, Xiancai Li, Letu Ji, Chuntao Zheng, Zhiqiang Xiang, Qinghua Sun, Hengcai Wang. Preclinical study of allogeneic CD19-CAR-DNT cells as an off-the-shelf immunotherapy drug for NHL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5510.
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Spanggord, Ronald J., i Lane A. Clizbe. "A reevaluation of the Hofmann rearrangement in electron deficient systems: preparation of 2-(15N)-amino-4,6-dinitrotoluene and 4-(15N)-amino-2,6-dinitrotoluene". Journal of Labelled Compounds and Radiopharmaceuticals 41, nr 7 (lipiec 1998): 615–21. http://dx.doi.org/10.1002/(sici)1099-1344(199807)41:7<615::aid-jlcr106>3.0.co;2-b.
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Nehrenheim, E., O. Muter, M. Odlare, A. Rodriguez, G. Cepurnieks i V. Bartkevics. "Toxicity assessment and biodegradation potential of water-soluble sludge containing 2,4,6-trinitrotoluene". Water Science and Technology 68, nr 8 (1.10.2013): 1707–14. http://dx.doi.org/10.2166/wst.2013.416.
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The water-soluble phase of trinitrotoluene-containing sludge (SLP) was characterized with regard to trinitrotoluene (TNT) concentration, ecotoxicity, and a model biodegradation experiment as evaluation criteria for further development of appropriate treatment technologies. SLP contained 67.8 mg TNT/l. The results of germination and root-elongation tests indicated that SLP had a species-specific phytotoxic effect. The results of a 21 day degradation experiment demonstrated TNT conversion to 4-amino-2,6-DNT and 2-amino-4,6-DNT, with a simultaneous reduction in the total concentration of nitroaromatics. Addition of inoculum stimulated the TNT degradation process. The presence of the sludge solid phase inhibited microbial activity. Measurement of microbial enzyme activity was used to assess changes in the microbial community during the biodegradation process.
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CHEN, YUNQING, HAIBO LIU i X. C. ZHANG. "EXPERIMENTAL AND DENSITY FUNCTIONAL THEORY STUDY ON THz SPECTRA OF 4-NT AND 2, 6-DNT". International Journal of High Speed Electronics and Systems 17, nr 02 (czerwiec 2007): 283–91. http://dx.doi.org/10.1142/s0129156407004503.
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Terahertz (THz) spectra of two TNT-related compounds (4-NT and 2, 6-DNT) are investigated using Fourier transform infrared spectroscopy (FTIR, 1.5-20 THz) and THz time-domain spectroscopy (THz-TDS, 0.2-2.5 THz). Density functional theory (DFT) is applied to calculate THz spectra of these two compounds. Transmission, diffuse reflection, and calculated spectra are in good agreement. The measured THz resonance lines from the transmission and diffuse reflectance spectra are assigned based on the DFT simulation. The observed THz signatures imply that THz spectrum has potential for standoff detection of explosives and related compounds (ERCs) in the THz range.
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LI, SONG, YOSHITO KUMAGAI, MINAKO KIRIYA-SAKAI i NOBUHIRO SHIMOJO. "Acetylation of 4-amino-2, 6-dinitrotoluene, a Major Metabolite of 2, 4, 6-trinitrotoluene by Liver Cytosol of SD Rats". SANGYO EISEIGAKU ZASSHI 40, nr 6 (1998): 252–53. http://dx.doi.org/10.1539/sangyoeisei.kj00001990684.
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Huang, Shouqin, Paul A. Lindahl, Chuanyue Wang, George N. Bennett, Frederick B. Rudolph i Joseph B. Hughes. "2,4,6-Trinitrotoluene Reduction by Carbon Monoxide Dehydrogenase from Clostridium thermoaceticum". Applied and Environmental Microbiology 66, nr 4 (1.04.2000): 1474–78. http://dx.doi.org/10.1128/aem.66.4.1474-1478.2000.
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ABSTRACT Purified CO dehydrogenase (CODH) from Clostridium thermoaceticum catalyzed the transformation of 2,4,6-trinitrotoluene (TNT). The intermediates and reduced products of TNT transformation were separated and appear to be identical to the compounds formed by C. acetobutylicum, namely, 2-hydroxylamino-4,6-dinitrotoluene (2HA46DNT), 4-hydroxylamino-2,6-dinitrotoluene (4HA26DNT), 2,4-dihydroxylamino-6-nitrotoluene (24DHANT), and the Bamberger rearrangement product of 2,4-dihydroxylamino-6-nitrotoluene. In the presence of saturating CO, CODH catalyzed the conversion of TNT to two monohydroxylamino derivatives (2HA46DNT and 4HA26DNT), with 4HA26DNT as the dominant isomer. These derivatives were then converted to 24DHANT, which slowly converted to the Bamberger rearrangement product. ApparentKm and k cat values of TNT reduction were 165 ± 43 μM for TNT and 400 ± 94 s−1, respectively. Cyanide, an inhibitor for the CO/CO2 oxidation/reduction activity of CODH, inhibited the TNT degradation activity of CODH.
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MISZCZAK, Maciej. "POLISH DISCLOSED SECRET PATENTS ON TECHNOLOGY OF INDIVIDUAL HIGH EXPLOSIVES". PROBLEMY TECHNIKI UZBROJENIA 163, nr 1 (12.05.2023): 75–92. http://dx.doi.org/10.5604/01.3001.0053.5919.
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Results of searches and analyses of the Polish disclosed secret patents on technology of high-explosives in the form of such chemical individuals as nitrostarch, trotyl, dinitrotoluene, tetryl, penthrite, hexogen and octogen, are presented in the paper. As a result of the above searches, nine patent descriptions [1-9] of inventions were found, and among them three [2-4] dealt with nitrostarch stabilization, one [1] with stabilization of penthrite and hexogen, one [6] with trotyl cleaning from post-nitrating acids, one [7] with trotyl and dinitrotoluene drying, and three [5,8,9] with obtainment of tetryl, trotyl and octogen, respectively. The inventions were applied as secret ones to the Patent Office in 1948-1996, and the secrecy clause was lifted from them by the announcements of the News of the Patent Office of the Republic of Poland in 2007-2016.
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Dowdell, Kennichi, Julie Niemela, Susan Price, Joie Davis, Katie Perkins, Janet Dale, Jennifer M. Puck i in. "Somatic Fas Mutations Account for Nearly One Third of Autoimmune Lymphoproliferative Syndrome (ALPS) Cases with Previously Unknown Genetic Mutations." Blood 114, nr 22 (20.11.2009): 710. http://dx.doi.org/10.1182/blood.v114.22.710.710.
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Abstract Abstract 710 Background: Autoimmune lymphoproliferative syndrome (ALPS) is characterized by childhood onset of lymphadenopathy, hepatosplenomegaly, autoimmune cytopenias, elevated (>1%) double negative T (DNT; CD3+, TCRalpha-beta+, CD4−, CD8−, B220+) lymphocytes in peripheral blood and an increased risk of lymphoma; primarily due to impaired lymphocyte apoptosis. Most cases (65%; 173 individuals in our cohort), known as ALPS Type Ia, are associated with dominant heterozygous germline mutations in the gene TNFRSF6 encoding the protein for CD95 (Fas, Apo-1). Another 5% of patients have mutations in FasL (Type Ib), caspases (Type II) or NRAS (Type IV). However, approximately 30% of ALPS patients in our cohort have no mutation found upon genomic sequencing of DNA from peripheral blood. We designated these patients as ALPS Type III (16%) if they met all the criteria of ALPS, i.e., elevated DNT cell numbers, nonmalignant chronic lymphadenopathy/splenomegaly and defective lymphocyte apoptosis by in vitro assay; we called them ALPS phenotype (14%) if they had all the features as described above but did not demonstrate an in vitro apoptosis defect. Holzelova et. al. (NEJM 2004; 351:1409) previously identified somatic Fas mutations in DNT cell population in 6 patients with ALPS phenotype. However, there was no information as to the proportion of ALPS patients expressing a somatic Fas mutation or any differences in their clinical phenotype. Methods and Results: Over the last 5 years we sought to determine the proportion of ALPS Type III and ALPS phenotype patients with somatic Fas mutations in their DNT cell population and to further clinically characterize these patients. DNT cells were purified to >50% by magnetic bead separation and DNA was sequenced for Fas. We found somatic Fas mutations in the DNT cells of 11/31 (35.5%) patients; 5/15 with ALPS Type III (5 males; age range = 1-17 years; median = 12 years), and 6/16 with ALPS phenotype (3 males and 3 females; age range = 3 mo–48 years; median age = 1 year). All the mutations clustered to an approximately 150 base region of the intracellular domain of Fas (exons 7, 8 and 9), except for one mutation in exon 3. All mutations resulted in functional loss of normal Fas signaling based on the mutation type or having been previously observed in ALPS Typa Ia. The somatic ALPS patients showed a similar clinical phenotype to that of ALPS Type Ia with increased DNT cell numbers (Median 6%; Range 4-19%), and increased levels of biomarkers like serum vitamin B12, IL-10 and sFasL. All 4 patients with onset of symptoms in infancy have required long-term treatment of their refractory autoimmune cytopenias with mycophenolate mofetil for the last 2-8years, while one of them underwent splenectomy. Inability to demonstrate defective lymphocyte apoptosis by in vitro testing of unseparated lymphocytes in ALPS phenotype patients with somatic Fas mutations is likely due to the relatively small number of affected cells (<20%) in their peripheral blood. Additionally, we hypothesize that the late onset of clinical disease in ALPS Type III patients with somatic Fas mutations may reflect the time required to accumulate a threshold number of cells that are able to confer clinical manifestations. Conclusion: Thus, the majority of somatic ALPS mutations can be detected by sequencing exons 7-9 of isolated DNT cell DNA. Patients with somatic Fas mutations now comprise the second largest group of known genetic mutations in ALPS, followed by patients with caspase 10, NRAS, caspase 8 and FasL germline mutations, respectively. We recommend testing for somatic Fas mutations in ALPS Type III patients (particularly those with late onset) and all ALPS phenotype patients, using ungated DNT purities of >50%. These data also highlight the role of somatic mutations in the pathogenesis of nonmalignant hematological conditions in adults and children, as well as in clonal malignancies. Disclosures: No relevant conflicts of interest to declare.
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Lin, Chuan-Min, Hsiu-Chuan Wu, Yi-Ming Wu, Chi-Hung Liu, Kuo-Hsuan Chang, Ting-Yu Chang, Kuo-Lun Huang i in. "Computed Tomography Angiography in Acute Stroke Patients Receiving Recombinant Tissue Plasminogen Activator: Outcome and Safety Evaluations in an Asian Population". Cerebrovascular Diseases 49, nr 1 (2020): 62–69. http://dx.doi.org/10.1159/000504776.
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Introduction: The multiphase computed tomography angiography (mCTA) is superior to the noncontrast computed tomography (NCCT) in selecting patients that would benefit from mechanical thrombectomy following an acute ischemic stroke (AIS). It remains unclear whether the longer examination time of mCTA worsens outcomes of intravenous recombinant tissue plasminogen activator (IV r-tPA) or increases the risk of hemorrhagic transformation (HT) compared to NCCT in Asian stroke patients. Methods: Between January 2011 and December 2017, 199 AIS patients receiving IV r-tPA with initial National Institute of Health Stroke Scale (NIHSS) scores between 6 and 25 were enrolled in a single medical center. Onset-to-needle time (ONT), door-to-needle time (DNT), and creatinine levels before and after thrombolysis were recorded. We evaluated NIHSS scores 2, 24 h after treatment, and at discharge, the modified Rankin Scale (mRS) at discharge, and mortality rate. The presence of HT was reviewed within 7 days after thrombolysis. Results: DNT, perithrombolysis creatinine levels, NIHSS, and mRS scores at the emergency room were similar between the NCCT and mCTA groups. ONT was shorter in the mCTA group. AIS patients got more significant neurologic improvement (NIHSS decrease ≥4) after thrombolysis and physically independent (mRS ≤2) at discharge in the mCTA group. Mortality rates, symptomatic, and total HT rates were similar between the NCCT and mCTA groups. Conclusion: Comparing to NCCT, mCTA-based IV r-tPA would not delay DNT nor worsen the outcome. Furthermore, mCTA provides more information for early identification of candidates for mechanical thrombectomy in Asian AIS patients.
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Gyure, Kymberly A., Glenn D. Sandberg, Richard A. Prayson, Alan L. Morrison, Regina C. Armstrong i Kondi Wong. "Dysembryoplastic Neuroepithelial Tumor". Archives of Pathology & Laboratory Medicine 124, nr 1 (1.01.2000): 123–26. http://dx.doi.org/10.5858/2000-124-0123-dnt.
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Abstract Context.—The dysembryoplastic neuroepithelial tumor (DNT) is an uncommon lesion characterized by a heterogeneous population of neurons, astrocytes, and oligodendroglia-like cells (OLCs). The basic nature of the DNT and its constituent cells, particularly the OLCs, remains unresolved; some authors favor a neuronal origin, and others propose a glial or mixed origin for these cells. Design.—We examined 11 DNTs with antibodies to myelin oligodendrocyte glycoprotein, a marker of mature oligodendrocytes. Results.—All DNTs studied (7 from males, 4 from females; age range of patients, 2–37 years) were composed of varying proportions of neurons, astrocytes, and OLCs. Membrane or cytoplasmic immunoreactivity for myelin oligodendrocyte glycoprotein was found in many OLCs in 9 of 11 cases. The number of myelin oligodendrocyte glycoprotein–positive OLCs was variable: >75% of the OLCs were positive in 5 cases, 25% to 75% of the OLCs were positive in 2 cases, and <25% of the OLCs were positive in 2 cases. Conclusion.—These findings suggest that many of the OLCs represent mature oligodendrocytes and support the notion that DNTs are heterogenous lesions composed of multiple, mature cell types.
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Houpt, John T., Glenn J. Leach, Larry R. Williams, Mark S. Johnson i Gunda Reddy. "Toxicity Assessment of 4-Amino-2-Nitrotoluene". International Journal of Toxicology 32, nr 2 (marzec 2013): 113–22. http://dx.doi.org/10.1177/1091581813480408.
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4-Amino-2-nitrotoluene (4A2NT; CAS 119-32-4) is a degradation product of 2,4-dinitrotoluene. The toxicity data on 4A2NT are limited. Therefore, we collected toxicity data from rats to assess environmental and human health effects from exposures. The approximate lethal dose for both sexes was 5000 mg/kg. A 14-day toxicity study in rats was conducted with 4A2NT in the feed at concentrations of 0, 125, 250, 500, 1000, and 2000 ppm. Based on a 14-day oral dose range toxicity study with 4A2NT in the feed, 2000 ppm was selected as highest concentration for a subsequent 90-day study. An oral 90-day subchronic toxicity study in rats was conducted with concentrations of 0, 500, 1000, or 2000 ppm of 4A2NT in the feed. The calculated consumed doses of 4A2NT in the feed were 0, 27, 52, or 115 mg/kg/d for males and 0, 32, 65, or 138 mg/kg/d for females. A no-observed adverse effect level could not be determined. The lowest observed adverse effect level was 27 mg/kg/d for males and 32 mg/kg/d for female rats based upon decreased body weight gain. The decreased body weight gain in male rats was the most sensitive adverse event observed in this study and was used to derive a benchmark dose (BMD). A BMD of 23.1 mg/kg/d and BMD with 10% effect level of 15.5 mg/kg/d were calculated for male rats, which were used to derive an oral reference dose (RfD). The human RfD of 1.26 μg/kg/d was derived using current United States Environmental Protection Agency guidelines.
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BOULESNAM, Benmalek, Fahima HAMI, Djalal TRACHE i Toudert AHMED ZAID. "HPLC Method Development for the Fast Separation of a Complex Explosive Mixture". ENP Engineering Science Journal 1, nr 1 (22.07.2021): 75–83. http://dx.doi.org/10.53907/enpesj.v1i1.17.
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The growing threat of terrorism in many parts of the world has called for the urgent need to find rapid and reliable means of analyzing explosives. This is in view to help forensic scientists to identify different swabs from post-blast debris. The present study aims to achieve an efficient separation and identification of a mixture of sixteen explosive compounds (including nitroaromatics, nitramines, and nitrate esters) by high performance liquid chromatography using a diode array detection (HPLC/DAD) and an Agilent Poroshell 120 EC-120 C18 column at two wavelengths (235 and 214 nm). Relevant chromatographic parameters such as capacity factors, resolution, selectivity and number of theoretical plates have been optimized in order to achieve the best separation of the different components. In this respect, the effects of various parameters such as gradient time, column temperature, flow rate of mobile phase and initial percentage organic mobile phase on the separation of these compounds were investigated. It was revealed that the method allowed a fairly acceptable separation of all the compounds in less than 15 minutes except for two isomers, namely 4-A-2,6-DNT, 2-A-4,6-DNT and 2,6- DNT which could not be resolved by the used C18 column. This shortcoming notwithstanding, the developed method produced satisfactory results and demonstrated sensitive and robust separation, furthermore indicating that the HPLC developed method can be both fast and efficient for the analysis of complex mixtures of explosive compounds.
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Cooper, Nichola, V. Koneti Rao, Thomas Fleisher i James B. Bussel. "Lymphocyte Homeostasis FAS Pathway Is Altered in Some Patients with Immune Thrombocytopenia." Blood 114, nr 22 (20.11.2009): 3514. http://dx.doi.org/10.1182/blood.v114.22.3514.3514.
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Abstract Abstract 3514 Poster Board III-451 Patients with autoimmune lymphoproliferative syndrome (ALPS) are the only described patients in which a known genetic defect leads directly to autoimmunity. In these patients, mutations in FAS or FASL result in an inability of activated lymphocytes to die resulting in defective lymphocyte homeostasis. The disorder manifests itself in autoimmunity directed towards platelets, red cells and neutrophils in addition to lymphadenopathy, splenomegaly and an increased risk of lymphoma. Inheritance of the defect is dominant, however there is variable penetration and patients even within the same family and with the same mutation can have a different phenotype. A definitive diagnosis requires clinical symptoms, elevated (>1%) TCRab+CD3+CD4-CD8- (DNT) cells in the peripheral blood and the demonstration of defective lymphocyte apoptosis in vitro. Given the tendency for patients with ALPS to develop ITP, we hypothesised that patients with ITP may also have mutations or polymorphisms within this pathway and hence abnormal lymphocyte homeostasis as an etiology of their ITP. DNA from 88 children and adults with chronic ITP (48 post splenectomy, all more than 1 year from diagnosis) were screened for mutations in the FAS gene. None had the mutations typically associated with ALPS. However, in 6 patients single nucleotide polymorphisms (SNPs) were detected: 3 at 528(+6)C>T and 3 at 836C>T; one patient had both polymorphisms. Three of these patients also had haemolysis. In three patients, FAS induced apoptosis studies were normal (the remaining await analysis). DNT cells (the signature cells of ALPS) ranged from 0.5% to 2.9% in these 6 patients with all but one above the normal adult range (0.1-0.9%). DNT cells were also raised in 3 of 4 patients with no SNPs in FAS, (median 1.8 - range 1.1 to 6.1%). One individual with the 836C>T SNP had 2.9% DNT cells with an absolute number of 91 cells (DNT cells NR 2-17 cells) with virtually absent gamma-delta DNTs. In addition, this patient had evidence activation of T cells with raised CD4/HLA-DR. and CD8/HLA-DR and CD27+ B cells were <16% of B cells. This patient had severe ITP with a complete response to rituximab for the last 8 years. This data, although not quite conclusive, suggests that SNPs in the FAS pathway may contribute to the autoimmunity seen in patients with ITP. In addition, the presence of increased DNT cells, even in patients without SNPs in the FAS gene, suggests defect in the immune system not previously investigated and that the DNT cells may have a role in immune homeostasis. Disclosures: Cooper: GSK: Consultancy, Honoraria; Amgen: Consultancy. Bussel:Genzyme: Research Funding; GlaxoSmithKline: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cangene: Research Funding; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Immunomedics: Research Funding; Ligand: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eisai, Inc: Research Funding; Sysmex: Research Funding; Scienta: Speakers Bureau; Shionogi: Membership on an entity's Board of Directors or advisory committees.
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Matucci Cerinic, C., L. Oliveira Mendonca, M. Miano, P. Terrnaova, F. Casabona, M. Bustaffa, F. Bovis i in. "THU0501 EARLY DIAGNOSIS OF THE AUTOIMMUNE LYMPHOPROLIFERATIVE SYNDROME (ALPS) IN PATIENTS WITH UNDEFINED AUTOINFLAMMATORY OR AUTOIMMUNE DISORDERS: THE PRACTICAL ROLE OF A FLOW CYTOMETRY PANEL". Annals of the Rheumatic Diseases 79, Suppl 1 (czerwiec 2020): 489.1–489. http://dx.doi.org/10.1136/annrheumdis-2020-eular.3795.
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Background:ALPS is a rare disorder due to a defective apoptotic mechanism leading to abnormal lymphoproliferation and autoimmunity. The disease is difficult to identify in the early phase when it may be misdiagnosed. Elevated TCR alpha-beta CD4-CD8- lymphocytes (double negative T lymphocytes DNT) together with hyperIgG, high levels of IL10, Il18, vitamin B12 and soluble Fas ligand have been suggested as the main ALPS hallmarks (1). Therefore, a specific flow cytometry panel (DNT cells, ratio of CD25+CD3+ to HLA−DR+CD3+ cells, increased B220+ T-cells, and decreased CD27+ memory B cells) has been proposed to serve as a diagnostic screen for ALPS (2).Objectives:To evaluate the usefulness of a specific lymphocyte flow cytometry panel in the early identification of ALPS/ALPS-like disorders in a cohort of patients with undefined autoinflammatory or autoimmune disorders.Methods:The clinical data of patients referred to the pediatric Rheumatology Unit of the Istituto Giannina Gaslini Hospital for a suspicion of autoimmune or autoinflammatory condition from October 2015 to April 2018, were retrospectively analyzed. Data on clinical manifestations, laboratory workup, genetic analysis and treatment were collected. Flow cytometry was included among the screening panel: DNT, CD25+CD3+, HLA−DR+CD3+ cells, B220+ T-cells, and CD27+ memory B cells were included. A statistical analysis was performed: data were analyzed with an univariate logistic regression analysis, to identify the most significant variables associated with ALPS. These variables were then included in a multivariate analysis to select a set of clinical and laboratory parameters, each of them associated with a significant probability to be associated with ALPS independently from other variables.Results:475 patients were retrospectively analized. 211 patients not fulfilling the inclusion criteria were excluded. The patients were classified as follows: i) Autoimmune disease 26 pts (10 SLE; 3 MCTD; 6 jDM; 5 Behçet; 1 SjS; 1 Kawasaki) ii) Juvenile Idiopathic Arthritis 35 pts iii) Monogenic systemic autoinflammatory disease (MSAID) 27 pts (17 FMF; 3 MKD; 1 TRAPS; 4 DADA2; 2 SAVI) iv) PFAPA 100 pts v) Systemic Undefined Recurrent Fever 45 pts vi) Undetermined-SAID 15 pts vii) ALPS/ ALPS probable 16 pts. The flow cytometry panel showed, as expected, an elevation of DNT in all ALPS patients. Among the other parameters, CD3CD25+/CD3HLADR+, and B220+ T cells, were significatively altered in 75% of ALPS patients. Conversely, B CD27+ did not differentiate ALPS from the other subgroups. The multivariate analysis revealed 5 clinical/laboratory parameters that showed the higher independent association to ALPS in the cohort of patients. Splenomegaly, female gender, elevated DNT, arthralgia and elevated alfabeta+B220+ lymphocytes were positively and significantly associated to ALPS.Conclusion:The use of the specific flow cytometry panel, comprehensive of DNT, B220+, HLA-DR and CD25, in patients with undefined autoinflammatory or autoimmune disorders may identify a subgroup of patients with ALPS.References:[1]Joao B. Oliveira et al. Blood 2010; 116 (14): e35–e40.[2]Lenardo MJ et al.Immunity. 2010;32(3):291–295.Disclosure of Interests:Caterina Matucci Cerinic: None declared, Leonardo Oliveira Mendonca: None declared, maurizio miano: None declared, paola terrnaova: None declared, federica casabona: None declared, Marta Bustaffa: None declared, Francesca Bovis: None declared, Roberta Caorsi: None declared, Stefano Volpi: None declared, Angelo Ravelli: None declared, Carlo Dufour: None declared, Marco Gattorno Consultant of: Sobi, Novartis, Speakers bureau: Sobi, Novartis
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Chen, Wen-Shing, i Min-Chih Hsu. "Ultrasound-Assisted Mineralization of 2,4-Dinitrotoluene in Industrial Wastewater Using Persulfate Coupled with Semiconductors". Molecules 28, nr 11 (25.05.2023): 4351. http://dx.doi.org/10.3390/molecules28114351.
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Oxidative degradation of 2,4-dinitrotoluenes in aqueous solution was executed using persulfate combined with semiconductors motivated by ultrasound (probe type, 20 kHz). Batch-mode experiments were performed to elucidate the effects of diverse operation variables on the sono-catalytic performance, including the ultrasonic power intensity, dosage of persulfate anions, and semiconductors. Owing to pronounced scavenging behaviors caused by benzene, ethanol, and methanol, the chief oxidants were presumed to be sulfate radicals which originated from persulfate anions, motivated via either the ultrasound or sono-catalysis of semiconductors. With regard to semiconductors, the increment of 2,4-dinitrotoluene removal efficiency was inversely proportional to the band gap energy of semiconductors. Based on the outcomes indicated in a gas chromatograph–mass spectrometer, it was sensibly postulated that the preliminary step for 2,4-dinitrotoluene removal was denitrated into o-mononitrotoluene or p-mononitrotoluene, followed by decarboxylation to nitrobenzene. Subsequently, nitrobenzene was decomposed to hydroxycyclohexadienyl radicals and converted into 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol individually. Nitrophenol compounds with the cleavage of nitro groups synthesized phenol, which was sequentially transformed into hydroquinone and p-benzoquinone.
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Alvarez, Marc A., Christopher L. Kitts, Pat J. Unkefer i James L. Botsford. "Pseudomonas aeruginosastrain MA01 aerobically metabolizes the aminodinitrotoluenes produced by 2,4,6-trinitrotoluene nitro group reduction". Canadian Journal of Microbiology 41, nr 11 (1.11.1995): 984–91. http://dx.doi.org/10.1139/m95-137.
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Many microbes reduce the nitro substituents of 2,4,6-trinitrotoluene (TNT), producing aminodinitrotoluenes (ADNTs). These compounds are recalcitrant to further breakdown and are acutely toxic. In a search for organisms capable of metabolizing ADNTs, a bacterial strain was isolated for the ability to use 2-aminobenzoate (anthranilate) as sole C-source. This isolate, Pseudomonas aeruginosa MA01, metabolized TNT by first reducing one nitro group to form either 2-amino-4,6-dinitrotoluene (2ADNT) or 4-amino-2,6-dinitrotoluene (4ADNT). However, strain MA01 was distinct from other TNT-reducing organisms in that it transformed these compounds into highly polar metabolites through an O2-dependent process. Strain MA01 was able to cometabolize TNT, 2ADNT, and 4ADNT in the presence of a variety of carbon and energy sources. During aerobic cometabolism with succinate, 45% of uniformly ring-labeled [14C]TNT was transformed to highly polar compounds. Aerobic cometabolism of purified [14C]2ADNT and [14C]4ADNT with succinate as C-source produced similar amounts of these polar metabolites. During O2-limited cometabolism with succinate as C-source and nitrate as electron acceptor, less than 8% of the [14C]TNT was transformed to polar metabolites. Purified 2,6-diamino-4-nitrotoluene was not metabolized, and while 2,4-diamino-6-nitrotoluene was acetylated, the product (N-acetyl-2,4-diamino-6-nitrotoluene) was not further metabolized. Therefore, strain MA01 metabolized TNT by oxidation of the ADNTs and not by reduction the remaining nitro groups on the ADNTs.Key words: 2,4,6-trinitrotoluene, aminodinitrotoluene, Pseudomonas aeruginosa, cometabolism.
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Pak, Jeong W., Kyle L. Knoke, Daniel R. Noguera, Brian G. Fox i Glenn H. Chambliss. "Transformation of 2,4,6-Trinitrotoluene by Purified Xenobiotic Reductase B from Pseudomonas fluorescensI-C". Applied and Environmental Microbiology 66, nr 11 (1.11.2000): 4742–50. http://dx.doi.org/10.1128/aem.66.11.4742-4750.2000.
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ABSTRACT The enzymatic transformation of 2,4,6-trinitrotoluene (TNT) by purified XenB, an NADPH-dependent flavoprotein oxidoreductase fromPseudomonas fluorescens I-C, was evaluated by using natural abundance and [U-14C]TNT preparations. XenB catalyzed the reduction of TNT either by hydride addition to the aromatic ring or by nitro group reduction, with the accumulation of various tautomers of the protonated dihydride-Meisenheimer complex of TNT, 2-hydroxylamino-4,6-dinitrotoluene, and 4-hydroxylamino-2,6-dinitrotoluene. Subsequent reactions of these metabolites were nonenzymatic and resulted in predominant formation of at least three dimers with an anionic m/z of 376 as determined by negative-mode electrospray ionization mass spectrometry and the release of ∼0.5 mol of nitrite per mol of TNT consumed. The extents of the initial enzymatic reactions were similar in the presence and in the absence of O2, but the dimerization reaction and the release of nitrite were favored under aerobic conditions or under anaerobic conditions in the presence of NADP+. Reactions of chemically and enzymatically synthesized and high-pressure liquid chromatography-purified TNT metabolites showed that both a hydroxylamino-dinitrotoluene isomer and a tautomer of the protonated dihydride-Meisenheimer complex of TNT were required precursors for the dimerization and nitrite release reactions. The m/z 376 dimers also reacted with either dansyl chloride or N-1-naphthylethylenediamine HCl, providing evidence for an aryl amine functional group. In combination, the experimental results are consistent with assigning the chemical structures of them/z 376 species to various isomers of amino-dimethyl-tetranitrobiphenyl. A mechanism for the formation of these proposed TNT metabolites is presented, and the potential enzymatic and environmental significance of their formation is discussed.
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HODGSON, H. H. "The Apparent Anomalous Monoreduction of 2:4-Dinitrotoluene explained on the Theory of Hyperconjugation (The Baker-Nathan Effect)". Journal of the Society of Dyers and Colourists 62, nr 4 (22.10.2008): 114–15. http://dx.doi.org/10.1111/j.1478-4408.1946.tb02402.x.
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Shevelev, Svyatoslav A., Alexander Kh Shakhnes, Bogdan I. Ugrak i Sergei S. Vorob'ev. "HIGHLY SELECTIVE ONE-STEP SYNTHESIS OF 2-AMINO-4,6-DINITROTOLUENE AND 2,6-DIAMINO-4-NITROTOLUENE FROM 2,4,6-TRINITROTOLUENE". Synthetic Communications 31, nr 17 (1.01.2001): 2557–61. http://dx.doi.org/10.1081/scc-100105379.
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